1. Field of the Invention
The present invention is directed to chemically produced colored smokes. More particularly, the invention is directed to an in situ dye smoke which burns efficiently and without flame.
2. Description of the Prior Art
Dye smoke currently in use contain potassium chlorate (KClO.sub.3) oxidizer and pressed sugar-type binders. Liquid castable colored smoke compositions are known utilizing polymeric fuel binders such as polyacrylate, polyurethane or polyester which is then plasticized utilizing plasticizers such as bis-dinitropropylacrylate-formal, trimethylol ethane trinitrate or triethylene glycol dinitrate. These systems produce smoke by oxidizing the binder. The resulting heat volatilizes the dye. The gaseous dye then condenses in the air producing a colored smoke cloud. These systems are characterized by the destruction of part of the dye during the dispersion or volatilization process.
Compositions for chemically producing colored smokes are also known. The composition employs an iodine-based oxidizer and suitable fuel so that on combustion, either iodine or colored metallic iodides or both are formed. The color of the smoke is due to the reaction products and cannot be destroyed by the heat from the reaction. These compositions contain an oxidizer such as iodic acid, iodine pentoxide or a heavy metal iodate and a fuel binder such as polyvinyltetrazole resin which also contains a light metal fuel such as aluminum, magnesium, titanium, boron and zirconium.
The oxidizer and fuel of conventional smoke systems burn predominantly outside the smoke cannister, resulting in flaming. The flames can start brush fires if the smoke is used as a marker. Oxidizers such as potassium chlorate and light metal fuels such as aluminum and magnesium generate large amounts of heat which pyrolyze the dye. This destruction of part of the dye reduces the efficiency of the dye smoke.